He identifies one of the causes of this, namely, the fact the schools in question aren’t properly accountable to parents. At present, the school league tables don’t contain enough information to enable parents to make a properly informed judgment about how well a school is performing. Most parents just pay attention to the column indicating what percentage of children managed to get five good GCSEs, including Maths and English, without telling them what other subjects the children achieving this benchmark were studying. As Katharine Birbalsingh pointed out earlier today, too many schools have been steering their pupils towards BTECs in soft subjects like ‘Hair and Beauty’ and ‘Travel and Tourism’ to boost their league table ranking because those subjects are worth the equivalent of two or more GCSEs at grade C. Once you introduce a column measuring how many children manage to get good CCSEs in Maths, English, a Foreign Language, Geography or History and at least two Science subjects – the EBacc subjects – the numbers fall dramatically. The English average according to the old measure, where the only stipulated subjects are Maths and English, is 58.3%. According to the EBacc measure, it’s 16.5%.

Thankfully, the government is doing something about this. Not only is it introducing an EBacc column to the school league tables, it’s removing the GCSE equivalence status of most vocational qualifications. That means under-performing schools won’t be able to hide so easily in the school league tables.

However, there’s another cause of under-performance in rural state schools and that’s the absence of any competition. In areas like London, parents often have a choice of more than one state school. Catchment areas will overlap and there’s are usually alternative ways of qualifying for places other than proximity to the school gates. In rural areas, by contrast, there’s often only one state school for miles around so the only choice is to plump for the local school or go private. For middle-income or low-income families, that isn’t any choice at all.

It’s the lack of any competition that enables these “sink” middle-class schools to “muddle through”. After all, the vast majority of parents in the surrounding areas will have no choice but to send their children to these schools, regardless of how poorly they perform.

As the Prime Minister rightly points out, academies and free schools are capable of “smashing” this “complacency”. Earlier this year, a couple of social scientists at the LSE, Stephen Machin and James Vernoit, carried out a study of the 209 academies that opened under the previous government. They didn’t simply look at the impact of these academies on the pupils who happened to be attending them, but on the pupils at the comprehensives next door as well. They found that the pupils at the neighbouring schools benefitted almost as much as those at the academies. Not surprisingly, similar studies in Michigan, Arizona and Texas have discovered that charter schools have a comparable impact on neighbouring high schools. Conclusion: increased competition drives up standards.

The problem is, it’s more difficult to get the Department for Education to approve an application to set up a free school in a rural area than it is an inner-city area. Why? Because there’s less likely to be a shortage of places in rural areas and they’re less likely to be in the bottom half of DCLG’s “deprivation index”. Neither of those two factors should be decisive, but they often are because the government doesn’t want to leave itself open to the charge that it’s financing the creation of surplus school places in affluent areas at a time when deprived areas are facing genuine shortages.

Earlier this year, Nick Clegg gave a speech in which he urged Michael Gove to make sure the next batch of free schools were “open to all children and not just the privileged few”. “I want to see all of them in poorer neighbourhoods,” he said. “Or in areas crying out for more school places.”

If the Prime Minister really wants to “smash” the “complacency” of these rural coasters, he should instruct the Secretary of State for Education to ignore the wishes of the Deputy Prime Minister and approve more free school applications in rural areas.